How scaling optical networks is soon to change

Carrier division multiplexing and spatial division multiplexing (CSDM) are both needed, argues Lumentum’s Brian Smith.

The era of coherent-based optical transmission as is implemented today is coming to an end, argues Lumentum in a White Paper. 

Brian Smith

The author of the paper, Brian Smith, product and technology strategy, CTO Office at Lumentum, says two factors account for the looming change.

One is Shannon’s limit that defines how much information can be sent across a communications channel, in this case an optical fibre.

The second, less discussed regarding coherent-based optical transport, is how Moore’s law is slowing down.

”Both are happening coincidentally,” says Smith. “We believe what that means is that we, as an industry, are going to have to change how we scale capacity.”

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Oclaro makes available its EMLs and backs 400G-FR4

Lumentum’s plan to acquire Oclaro for $1.8 billion may have dominated the news at last month’s OFC show held in San Diego, but it was business as usual for Oclaro with its product and strategy announcements.

Adam Carter, chief commercial officer (pictured), positions Oclaro’s announcements in terms of general industry trends. 

“On the line side, everywhere there are 100-gigabit and 200-gigabit wavelengths, you will see that transition to 400 gigabit and 600 gigabit,” he says. “And on the client side, you have 100 gigabit going to 400 gigabit.” 

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Xtera demonstrates 40 Terabit using Raman amplification

Feature: 100 Gig and Beyond. Part 2

• Xtera's Raman amplification boosts capacity and reach
• 40 Terabit optical transmission over 1,500km in Verizon trial
• 64 Terabit over 1,500km in 2015 using a Raman module operating over 100nm of spectrum  

Herve Fevrier

Optical transport equipment makers continue to research techniques to increase the data carried long distances over a fibre without sacrificing reach. The techniques include signal processing of the transmit signal to cram data-carrying channels closer in the C-band, advanced soft-decision forward error correction (SD-FEC) and receiver signal processing to counter transmission impairments.

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